Valli



No. 430,563. Patented June 17, 18190.

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' tumbler-lock With bit-key.

NUNITED STATES PATENT OEEICE.

GIOSEF ANDREA CAVALLI, OF SAN MATEO, CALIFORNIA, ASSIGNOR OF ONE-HALF TO CHARLES N. KIRKBRIDE AND RICHARD H. JURY, OF

SAME PLACE.

KEY-HOLE GUARD.

SPECIFICATION forming part of Letters Patent No. 430,563, dated June 17, 1890.

Application iiled October 7, 1889.

To all whom it may concern:

Be it known that I, GiosEE ANDREA CA- VALLI, a citizen of the United States, residing at San Mateo, in the county of San Mateo and State of California', have invented certain new and useful Improvements in Door-Locks, of which the following'is a specification.

My invention has for its object animprovement in locks having a barrel-key and a pin or shaft that sets into the barrel of the key, by which such class of locks can be opened from either side. As an attachment to the ordinary tumbler-lock, this improvement is designed to afford greater security against the use of false keys or instruments to pick the lock than is obtained by the common To such ends and purpose my invention consists in a novel construction and combination of sliding pin or shaft fitting the eye of the key-hole on both sides of the door and adapted to receive and form a guide for the barrel of the key.

The following description explains the manner in which I proceed to construct and apply the said improvement to a lock of ordinary construction.

Figure 1 represents the lock in side elevation, and Fig. 2 shows a vertical section taken transversely through the key-holes at the lower portion of the lock.

A indicates the body of the lock, and B B the two key-holes.

A2 are escutcheons or rims surrounding the key-holes.

C is a tubular shaft fitting closely the eye of the key-hole, but capable of sliding longitudinally in both key-holes, it being of suitable length to be set flush with the Wood- Serial No. 326,230. (No model.)

Work at the back of the lock, Where its improvement is applied to a rim-lock, as represented in Fig. 2, and its movement being limited by a collar or fixed Washer D on the iniddle of the tube inside the key-chamber A3.

C is a longitudinal slit in the tube C, of proper Width to take in the bit of the key, and E is a fixed pin in the tube that stands clear of the inner Walls of the tube and is of suiicient diameter to iit the barrel of the key. The Width and depth of the slit in the tube and the size of the center pin are varied in different locks and the keys are fitted accordingly, so that by sniiicient variation one lock cannot be opened except With its own key. As thus formed and applied to a rimlock, the tubular shaft guides the key into position and then rotates with itas the key is turned. The stop D brings the shaft into position to set the key Whereit strikes and is arrested by the shoulder g inside the lockchamber, and this adjustment is obtained by inserting the key and pressing it back as far as it will go.

Having thus fully described my invention,

' What I claim, and desire to secure by Letters Patent, is

In combination with a lock, the longitudinally-movable tubular shaft C, having a slit CX, adapted to receive the bit or shank of a key, and the central pin E to tit the barrel of the key applied to the keyholes of the lock for operation, as set forth.

In testimony that I claim the foregoing I have hereunto set my hand and seal.

G. ANDREA CAVALLI. [L. s] Vitnesses:

C. N. KIRKBEIDE, R. H. JUEY. 

